The present invention relates to a cathode ray tube device (hereinafter abbreviated as CRT), for picture display in a TV set or the like.
FIG. 1 is a lateral view of a conventional CRT, the upper part being shown in section. The front of this CRT (which is at the left side of FIG. 1) comprises a panel 1. Panel 1, a funnel 2, connected to the rear part of panel 1, and a neck (not shown in the drawing) installed at the rear of funnel 2, form the main construction. Panel 1 comprises a faceplate 1a and skirt 1b, skirt 1b being connected to the peripheral edges of faceplate 1a. Panel 1 and funnel 2 are made of glass, and are glass-soldered together with frit glass. A metal tension band 3, is wound around skirt 1b. The interior of the CRT is evacuated, atmospheric pressure tends to press the middle part of faceplate 1a and funnel 2 inward, causing skirt 1b to bulge slightly toward the outside. Referring to FIG. 2, the middle part of panel 1 and funnel 2 are subjected to compressive stress, while tensile stress occurs in the neighborhood of skirt 1b.
FIG. 3 an oblique view of part of the CRT in FIG. 1. Cross-hatching in FIG. 3 shows where tensile stress occurs. In general glass is strong in resisting compressive stress but relative weak in resisting tensile stress, causing the CRT to be susceptible to implosion. The skirt 1b, faceplate 1a, and funnel 2 have therefor been made of, thick glass. Conventional CRTs, especially the larger types, require an extremely thick skirt 1b, faceplate 1a and funnel 2 making the total weight of the CRT inconveniently heavy.